Machine translation of the Portuguese Wikipedia article (November 2026 version).
Porto Velho is a Brazilian municipality and the capital of the state of Rondônia. With a population of 460,434 inhabitants, according to data from the Brazilian Institute of Geography and Statistics (IBGE) collected during the 2022 Census, it is the most populous municipality in Rondônia and the fourth most populous in the North Region, behind only Manaus, Belém and Ananindeua. Among all Brazilian municipalities it is the 49th most populous, and in the same year it ranked as the 22nd most populous state capital in the country.
With an area of 34,090.95 km², Porto Velho is the largest state capital in the country, being larger than two Brazilian states (Alagoas and Sergipe), and surpassing whole countries such as Belgium and Israel. It is also the most populous border municipality in Brazil and the only state capital whose territory borders another country, namely Bolivia.
Located on the east bank of the Madeira River, in the North Region of Brazil, Porto Velho was founded by the American company Madeira Mamoré Railway Company on 4 July 1907, during the construction of the Madeira-Mamoré Railway, led by the American magnate Percival Farquhar. On 2 October 1914 it was legally established as a municipality of Amazonas, becoming the capital of the state of Rondônia in 1943, when the Federal Territory of Guaporé was created. In 1956 the territory was renamed Rondônia, and it was elevated to the category of state (subdivision) on 4 January 1982.
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